Re^2: How to Check whether the Function Parameter is a Scalar or a Hash

Be careful about ref $data. If it's blessed, your checks will fail. Whether or not that matters, of course, depends upon the needs of the particular program.

Cheers,
Ovid

New address of my CGI Course.

Comment on Re^2: How to Check whether the Function Parameter is a Scalar or a Hash

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Re^3: How to Check whether the Function Parameter is a Scalar or a Hash by sauoq (Abbot) on Oct 06, 2005 at 02:05 UTC
If it's blessed, your checks will fail. For some not very good definitions of fail... Maybe I'm missing your point? The way I see it, if anyone actually needs to heed your warning^† either they are clever enough to work it out on their own or their design is questionable and should probably be fixed. The documented behavior—`ref` returning the package a blessed ref has been blessed into—seems totally sane to me. If `ref` still returned "HASH" and you could find yourself in the position of unknowingly violating the documented interface for some thingy, I'd consider that a far worse failure condition; wouldn't you? It's true that Perl gives you enough rope to hang yourself with... but shouldn't we warn people about looping that rope around their neck instead of just warning them about an arbitrary foot long section of the rope itself? † For some reason, this reminds me of the warning on some blow dryers: "Do not use while showering or bathing." -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]

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Re^3: How to Check whether the Function Parameter is a Scalar or a Hash
by sauoq (Abbot) on Oct 06, 2005 at 02:05 UTC

If it's blessed, your checks will fail.

For some not very good definitions of fail...

Maybe I'm missing your point? The way I see it, if anyone actually needs to heed your warning^† either they are clever enough to work it out on their own or their design is questionable and should probably be fixed.

The documented behavior—ref returning the package a blessed ref has been blessed into—seems totally sane to me. If ref still returned "HASH" and you could find yourself in the position of unknowingly violating the documented interface for some thingy, I'd consider that a far worse failure condition; wouldn't you?

It's true that Perl gives you enough rope to hang yourself with... but shouldn't we warn people about looping that rope around their neck instead of just warning them about an arbitrary foot long section of the rope itself?

† For some reason, this reminds me of the warning on some blow dryers: "Do not use while showering or bathing."

-sauoq
"My two cents aren't worth a dime.";

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